A galaxy is 3.5 Mly away and is imaged with a CCD detector and telescope. The optics of the telescope and the sizes of the pixels in the camera are arranged thus that each pixel sees a 1.0 arc second piece of the sky. Find the physical size of the piece of the galaxy each pixel sees, in parsecs?
If the surface brightness of the galaxies nucleus is 22.3meter as per sq arc second, find the surface density assuming the stars emitting the light are essentially like our sun?